5.0 swap? Consider using the 4R70W !! | Page 2 | Ford Explorer Forums - Serious Explorations

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5.0 swap? Consider using the 4R70W !!

Public Service Message:

For those of your considering swapping in a 5.0L V8 and AOD in your explorer, consider using a 4R70W (aka: AODE-W) wide ratio electronic controlled transmission instead of a traditional AOD.

For those of you who don't know, I used a AOD (automatic Overdrive) in my Explorer V8 project. The AOD's torque conveter locks up in 3rd and Fourth gear by the use of a one piece lockup shaft in the transmission. This means that the torque multiplying effect only exists in 1st and 2nd gear. After completing my 5.0 swap, I wish I could have used an A4LD rather than the AOD. lol. The AOD is controlled by a mechanical linkage called a throttle valve cable. This cables tells your transmission how to shift......and it does a clunky job at best. I tend to drive in 3rd (D) instead of (OD) to avoid the constant "Hunt" that this inconsistent transmission resluts in. Imagine your racing somebody, as soon as you hit third gear, Your torque converter manually locks, shooting your RPM's down, which allows you to only build RPM dependent on your speed. This 3rd gear lockup is also bad for driving around in the city. Say, your driving in stop and go traffic, You get up to 25 MPH, and the cars start braking in front of, you let off the gas. At this point, the low TV pressure will enter the transmission in to a "Coast" mode, causing it to shift in to 3rd gear locked "CLUNK" Now, if the traffic starts accelerating, you would have to press the gas pedal down causing the motor to bog, to get it back in to 2nd gear.......
AOD = CLUNKY SHIFTS. The mechanical linkage can not predict the your future actions.

Now some people who live and die by the AOD have some fixes for this problem.
Fix #1: Install all the internals from a 4R70W in to the AOD to make it wide ratio & give it the 2in OD band. While this is a nice little mod, it still doesn't address the Torque Converter lockup issue.

Fix #2: Switch over to a NON-Lockup torque converter and one piece input shaft. Well this is just super!! Now I have to drive on the highway with an open torque converter at 5,000 RPM........ Good for RACING, not for the daily driver.....No thanks on this one.

But fear not......... THERE IS LIGHT at the end of the tunnel. And it is known as 4R70W.
The 4R70W looks just like the AOD and AODE, except for the slightly larger Bellhousing. The 4R70W has an Electronic Lock-up converter. This means it has the ability to lock and unlock allowing you to maintain the "torque multiplying effect" in any gear you want.

Here is an example of the 4R70W shifts:
1st gear: OPEN Torque COnverter
2nd gear: Optional Locked torque converter
3rd gear: Open torque converter
3rd gear: Optional locked torque converter
4th gear: (OD BAND) Open torque converter
4th gear: (OD Band) LOCKED torque conveter

This gives the versatility of seven different shift points compared to the AOD's four.

The 4R70W utilizes the Engines Throttle Postion sensor to more precisely and electronically control line pressure. It can even be used on a carburated 302 if a aftermarket sesnor is installed. In Conversions using a EEC-IV computer system, you can use a Baumann TCS from Baumann Engineering to operate the unit. Also, Since the 4R70W is the same shell as the AOD, you can use the Advanced Adapter tailshaft conversions made for any year AOD. The Baumann TCS computer that controls the 4R70W allows you to even input your tire size and rear axle gear ratio to further customize your shift points with the use of a labtop or desktop computer. Instead of using a mechanical governor, the 4R70W instead utilizes an output shaft speed sensoe seperate from the tailshaft/transfer case VSS sensor to further predict shifting.

So, my suggestion for anyone wanting a smooth shifting transmission to be used in a "road" or daily driver vehicle, look in to the 4R70W.

Think a 4R70W is expensive? Nope. I got a brand new model year 2000 4R70W with new torque converter for $699. If you plan on searching for an 4R70W here is soem advice for finding one. Try and stick to a model year 1998 and up 4R70W.......Ford upgraded to a mechanical diode and made a few other revisions that compliment the tranny. Do not get a 4R70W that came behind a 4.6L V8. This will not bolt up to a 5.0 "windsor bolt pattern. The 4R70W is used in many Ford Hi-performance applications including the new GT-40 concept, Cobra Mustangs, 4.6 Expeditions, 4.6 F-150's etc. You can find 4R70W's with the 5.0 windsor bolt pattern on 1996-2001 Explorer V8's and 1994+ F-150 V8's and on some other 3.8 V6 models....... Unless you are running a wiring harness that orignally had a 4R70W behind it, you must use a Baumann TCS computer, it is very SIMPLE to hook up (no complex wiring, just hook it up to your TPS and cehicle power and your set) Information on the computer can be found at www.baumannengineering.com
Hope this Helps!

Al - Phoenix, AZ asp84@earthlink.net

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Oh goodness more heavy lifting for the holidays.....

Joe, got any takers for your old Jet AOD?

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No, not yet. I can't say that I've tried to sell it yet. I paid $1350 plus another $300 for the torque converter. I'd like to get $1000 for it. It has about 2500 miles on it.

I'm using a factory torque converter. It seems to work really well and launches hard when pushed. I've surprise more then enough unsuspecting imports trying to beat me on the suicide lane.

How much is one of those Baumann TCS computers?

The Baumann COmputer is $400 dollars................... and is the only way to operate the 4R70W unless you use an EEC-V (five) computer system and wire harness.

Good Luck,